Kabul , Afghanistan -LRB- CNN -RRB- -- Another Taliban leader has been seized in neighboring Pakistan by security forces , sources said .

Mullah Abdul Salam was arrested last week , according to Afghan government officials , Taliban sources and a U.S. official .

Word of Salam 's arrest comes days after news of the capture of the Afghan Taliban 's reputed second-in-command , Mullah Abdul Ghani Baradar .

`` The Taliban is down another ` shadow governor , ' '' the American source said of Salam . The source declined to be named because of the sensitivity of the information .

The news came against the background of an intensified U.S.-led campaign against insurgents on both sides of the border .

Taliban fighters are resisting Operation Moshtarak , an allied military push into areas the Taliban control in southern Afghanistan 's Helmand province .

`` They know this is their last stronghold . They 're not backing down , '' CNN 's Atia Abawi reported from the battlefield , where she is embedded with U.S. Marines .

The crackle of small-arms fire and the whoosh of outgoing mortar rounds from the Marines were clearly audible on the line as she described the battle .

`` About five minutes ago , Taliban started attacking our area , '' she said shortly before 8 a.m. ET . `` The Taliban are not giving up -- they seem to be coming out in squads , -LSB- but -RSB- they know they ca n't group together in large numbers '' because it would make them easier targets .

The Taliban seem to include `` foreign fighters who will fight to the death , '' she said .

It will take NATO-led military forces `` another 25 to 30 days to secure that which needs to be secured '' in Helmand and a further three months to ensure insurgents are kept out of the area , British Maj. Gen. Nick Carter said Thursday in a briefing from Afghanistan broadcast by the Pentagon Channel .

The Nad-e Ali district is `` broadly secure , '' Carter said , noting there is still Taliban resistance in Marjah .

`` It will be some days before we can be completely confident that Marjah is secure , '' said Carter , the International Security Assistance Force 's head of Regional Command South .

Ten civilians were killed on the second day of the operation , he said . Reports at the time said 12 were killed .

There have been five casualties among the NATO-led forces during the operation , the forces said in a statement Thursday , without giving further details .

It said later that four ISAF servicemembers died Thursday -- two of them in an improvised explosive device strike ; another after a separate IED attack ; small-arms fire killed the fourth servicemember . It was not immediately clear whether the four were among the five casualties noted earlier . The four deaths bring to 44 the number of Americans killed this year in Afghanistan . In all , 78 coalition forces have died this year

Across the border in Pakistan , four people were killed and five were wounded Thursday when a drone fired on a suspected militant compound in the country 's tribal region , intelligence sources and a local political official said .

The four dead were suspected militants , two intelligence officials said . It was not clear whether the wounded also were militants .

The remote-controlled aircraft fired two missiles at the compound in the Danday Darpakhel area of North Waziristan , one of seven districts in the tribal region along the Afghan border , the sources said . They asked not to be identified because they are not authorized to speak to the media .

The U.S. military does not comment on reported attacks by the pilotless aircraft , but the United States is the only country operating in the region known to have the ability to launch missiles from drones .

Salam was arrested in Pakistan , the Afghan government and Taliban sources said , but they named different cities as the location of his capture .

Gov. Muhammad Omar of Afghanistan 's Kunduz province said Salam was detained in Quetta , where the Afghan Taliban reportedly has its leadership councils . The Taliban sources said he was nabbed in Faisalabad .

Salam is believed to be the Taliban commander for Kunduz , Omar said .

Salam was directing Taliban military operations in the province , including ordering terrorist actions , mine planting and suicide attacks , said Abdul Razaq Yaqubi , police chief in Kunduz .

Yaqubi said Salam and another Taliban `` shadow governor , '' Mullah Salih , were arrested last week in the Pakistani city of Peshawar . He said the information came from Pakistani authorities .

Salih was the shadow governor of Baghlan province , the police chief said . There was no immediate confirmation of Salih 's arrest .

Taliban sources and Omar said other suspected members of the Afghan Taliban were arrested with Salam , but their identities are not clear .

CNN 's Pam Benson in Washington and journalist Mati Matiullah in Kabul contributed to this report .

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NEW : NATO-led forces will secure Helmand in `` 25 to 30 days , '' British general says

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Mullah Abdul Salam arrested in Pakistan , say U.S. , Afghan , Taliban sources

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Salam is Taliban `` shadow governor '' of Afghanistan 's Kunduz province

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Four suspected militants reported killed in drone strike in Pakistan